ANGEO Annales Geophysicae ANGEO Ann. Geophys. 1432-0576 Copernicus Publications Göttingen, Germany 10.5194/angeo-25-219-2007 On the location of dayside magnetic reconnection during an interval of duskward oriented IMF Wild J. A. 1 Milan S. E. 2 Davies J. A. 3 Dunlop M. W. 3 Wright D. M. 2 Carr C. M. 4 Balogh A. 4 Rème H. 5 Fazakerley A. N. 6 Marchaudon A. 6 7 Dept. of Communication Systems, Lancaster University, Lancaster, LA1 4WA, UK Dept. of Physics & Astronomy, University of Leicester, Leicester, LE1 7RH, UK Rutherford Appleton Laboratory, Didcot, Oxfordshire, OX11 0QX, UK Blackett Laboratory, Imperial College, London SW7 2BZ, UK CESR/CNRS, 9 Avenue du Colonel Roche BP 4346, 31028 Toulouse, Cedex 4, France Mullard Space Science Laboratory, University College London, Holmbury St. Mary, Dorking, Surrey RH5 6NT, UK now at: LPCE/CNRS and Université d'Orléans, Orléans, France 01 02 2007 25 1 219 238 Copyright: © 2007 J. A. Wild et al. 2007 This work is licensed under the Creative Commons Attribution 3.0 Unported License. To view a copy of this licence, visit https://creativecommons.org/licenses/by/3.0/ This article is available from https://angeo.copernicus.org/articles/25/219/2007/angeo-25-219-2007.html The full text article is available as a PDF file from https://angeo.copernicus.org/articles/25/219/2007/angeo-25-219-2007.pdf

We present space- and ground-based observations of the signatures of magnetic reconnection during an interval of duskward-oriented interplanetary magnetic field on 25 March 2004. In situ field and plasma measurements are drawn from the Double Star and Cluster satellites during traversals of the pre-noon sector dayside magnetopause at low and high latitudes, respectively. These reveal the typical signatures of flux transfer events (FTEs), namely bipolar perturbations in the magnetic field component normal to the local magnetopause, enhancements in the local magnetic field strength and mixing of magnetospheric and magnetosheath plasmas. Further evidence of magnetic reconnection is inferred from the ground-based signatures of pulsed ionospheric flow observed over an extended interval. In order to ascertain the location of the reconnection site responsible for the FTEs, a simple model of open flux tube motion over the surface of the magnetopause is employed. A comparison of the modelled and observed motion of open flux tubes (i.e. FTEs) and plasma flow in the magnetopause boundary layer indicates that the FTEs observed at both low and high latitudes were consistence with the existence of a tilted X-line passing through the sub-solar region, as suggested by the component reconnection paradigm. While a high latitude X-line (as predicted by the anti-parallel description of reconnection) may have been present, we find it unlikely that it could have been responsible for the FTEs observed in the pre-noon sector under the observed IMF conditions. Finally, we note that throughout the interval, the magnetosphere was bathed in ULF oscillations within the solar wind electric field. While no one-to-one correspondence with the pulsed reconnection rate suggested by the ground-based observation of pulsed ionospheric flow has been demonstrated, we note that similar periodicity oscillations were observed throughout the solar wind-magnetosphere-ionosphere system. These findings are consistent with previously proposed mechanisms of solar wind modulation of the dayside reconnection rate.

 References Amm, O., Donovan, E F., Frey, H., Lester, M., Nakamura, R., Wild, J A., Aikio, A., Dunlop, M., Kauristie, K., Marchaudon, A., McCrea, I W., Opgenoorth, H J., and Strømme, A.: Coordinated studies of the Geospace environment using Cluster, satellite and ground-based data: An interim review, Ann. Geophys., 23, 2129–2170, 2005. Balogh, A., Dunlop, M W., Cowley, S. W H., Southwood, D J., Thomlinson, J G., Glassmeier, K.-H., Musmann, G., Lühr, H., Buchert, S., Acuña, M H., Fairfield, D H., Slavin, J A., Riedler, W., Schwingenschuh, K., and Kivelson, M G.: The Cluster magnetic fields investigation, Space Sci. Rev., 79, 65–91, 1997. Balogh, A., Carr, C M., Acuna, M H., Dunlop, M W., Beek, T J., Brown, P., Fornacon, K.-H., Georgescu, E., Glassmeier, K.-H., Harris, J., Musmann, G., Oddy, T., and Schwingenschuh, K.: The Cluster Magnetic Field Investigation: overview of in-flight performance and initial results, Ann. Geophys., 19, 1207–1217, 2001. Carr, C., Brown, P., Zhang, T L., Gloag, J., Horbury, T., Lucek, E., Magnes, W., O'Brien, H., Oddy, T., Auster, U., Austin, P., Aydogar, O., Balogh, A., Baumjohann, W., Beek, T., Eichelberger, H., Fornacon, K H., Georgescu, E., Glassmeier, K H., Ludlam, M., Nakamura, R., and Richter, I.: The Double Star magnetic field investigation: instrument design, performance and highlights of the first year's observations, Ann. Geophys., 23, 2713–2732, 2005. Cooling, B. M A., Owen, C J., and Schwartz, S J.: Role of magnetosheath flow in determining the motion of open flux tubes, J. Geophys. Res., 106, 18 763–18 775, 2001. Cowley, S. W H. and Lockwood, M.: Excitation and decay of solar wind-driven flows in the magnetosphere-ionosphere system, Ann. Geophys., 10, 103–115, 1992. Cowley, S. W H. and Owen, C J.: A simple illustrative model of open flux tube motion over the dayside magnetopause, Planet. Space Sci., 37, 1461–1475, 1989. Crooker, N U.: Dayside merging and cusp geometry, J. Geophys. Res., 84, 951–959, 1979. Davies, J A., Lester, M., and McCrea, I W.: A statistical study of ion frictional heating observed by EISCAT, Ann. Geophys., 15, 1399–1411, 1997. Davies, J A., Lester, M., and McCrea, I W.: Solar and seasonal dependence of ion frictional heating, Ann. Geophys., 17, 682–691, 1999. de~Hoffman, F. and Teller, E.: Magneto-hydrodynamic shocks, Phys. Rev., 80, 692, 1950. Dungey, J W.: Interplanetary field and the auroral zones, Phys. Res. Lett., 6, 47–48, 1961. Dunlop, M W. and Woodward, T I.: Multi-spacecraft discontinuity analysis: orientation and motion, in: Analysis methods for multi-spacecraft data, ISSI SR-001, pp. 271–305, ISSI, Bern, Switzerland, 1998. Dunlop, M W., Taylor, M. G. G T., Davies, J A., Owen, C J., Pitout, F., Fazakerley, A N., Pu, Z., Laakso, H., Bogdanova, Y V., Zong, Q.-G., Shen, C., Nykyri, K., Lavraud, B., Milan, S E., Phan, T D., Rème, H., Escoubet, C P., abd P Cargill, C. M C., Lockwood, M., and Sonnerup, B.: Coordinated Cluster/Double Star observations of dayside reconnection signatures, Ann. Geophys., 23, 2867–2875, 2005. Escoubet, C P., Schmidt, R., and Goldstein, M L.: Cluster – science and mission overview, Space Sci. Rev., 79, 391–391, 1997. Escoubet, C P., Fehringer, M., and Goldstein, M L.: The Cluster mission, Ann. Geophys., 19, 1197–1200, 2001. Fazakerley, A N., Carter, P J., Watson, G., Spencer, A., Sun, Y Q., Coker, J., Coker, P., Kataria, D O., Fontaine, D., Liu, Z X., Gilbert, L., He, L., Lahiff, A D., Mihaljcic, B., Szita, S., Taylor, M. G. G T., Wilson, R J., Dedieu, M., and Schwartz, S J.: The Double Star Plasma Electron and Current Experiment, Ann. Geophys., 23, 2733–2756, 2005. Fedorov, A., Dubinin, E., Song, P., Skalsky, A., and Budnik, E.: Structure of the flank magnetopause for horizontal IMF: INTERBALL 1 observations, J. Geophys. Res., 106, 25 419–25 436, 2001. Feldstein, Y I. and Starkov, G V.: Dynamics of auroral belt and geomagnetic disturbances, Planet. Space Sci., 15, 209–229, 1967. Gonzalez, W D. and Mozer, F S.: A quantitative model for the potential resulting from reconnection with an arbitrary interplanetary magnetic field, J. Geophys. Res., 79, 4186–4194, 1974. Greenwald, R A., Baker, K B., Dudeney, J R., Pinnock, M., Jones, T B., Thomas, E C., Villain, J P., Cerisier, J C., Senior, C., Hanuise, C., Hunsucker, R D., Sofko, G., Koehler, J., Nielsen, E., Pellinen, R., Walker, A. D M., Sato, N., and Yamagishi, H.: Darn/SuperDARN: a global view of the dynamics of high-latitude convection, Space Sci. Rev., 71, 761–796, 1995. Haerendel, G., Paschmann, G., Sckopke, N., Rosenbauer, H., and Hedgecock, P C.: The frontside boundary layer of the magnetopause and the problem of reconnection, J. Geophys. Res., 83, 3195–3216, 1978. Johnstone, A D., Alsop, C., Burge, S., Carter, P J., Coates, A J., Coker, A J., Fazakerley, A N., Grande, M., Gowen, R A., Gurgiolo, C., Hancock, B K., Narheim, B., Preece, A., Sheather, P H., Winningham, J D., and Woodliffe, R D.: PEACE: A Plasma Elctron And Current Instrument, Space Sci. Rev., 79, 351–398, 1997. Khotyaintsev, Y., Buchert, S., Stasiewicz, K., Vaivads, A., Savin, S., Papitashvili, V O., Farrugia, C J., Popielawska, B., and Tung, Y K.: Transient reconnection in the cusp during strongly negative IMF $B_Y$, J. Geophys. Res., 109, A04 204, https://doi.org/10.1029/2003JA009908, 2004. Kobel, E. and Flückiger, E O.: A model of the steady state magnetic field in the magnetosheath, J. Geophys. Res., 99, 23 617–23 622, 1994. Lester, M., Chapman, P., Cowley, S., Crooks, S., Davies, J., Hamadyk, P., McWilliams, K., Milan, S., Parsons, M., Payner, D., Thomas, E., Thornhill, J., Wade, N., Yeoman, T., and Barnes, R.: Stereo CUTLASS – A new capability for the SuperDARN HF radars, Ann. Geophys., 22, 459–473, 2004. Liu, Z X., Escoubet, C P., Pu, Z., Laakso, H., Shi, J K., Shen, C., and Hapgood, M.: The Double Star mission, Ann. Geophys., 23, 2707–2712, 2005. Longmore, M., Schwartz, S J., Geach, J., Cooling, B. M A., Dandouras, I., Lucek, E A., and Fazakerley, A N.: Dawn-dusk asymmetries and sub-Alfvénic flow in the high and low latitude magnetosheath, Ann. Geophys., 23, 3351–3364, 2004. Luhmann, J., Walker, R J., Russell, C T., Crooker, N U., Spreiter, J R., and Stahara, S S.: Patterns of potential magnetic field merging sites on the dayside magnetopause, J. Geophys. Res., 89, 1739–1742, 1984. Lühr, H., Aylward, A., Buchert, S C., Pajunpää, A., Pajunpää, K., Holmboe, T., and Zalewski, S M.: Westward moving dynamic substorm features observed with the IMAGE magnetometer network and other ground-based instruments, Ann. Geophys., 16, 425–440, 1998. McComas, D J., Bame, S J., Barker, P., Feldman, W C., Phillips, J L., Riley, P., and Griffee, J W.: Solar Wind Electron Proton Alpha Monitor (SWEPAM) for the Advanced Composition Explorer, Space Sci. Rev., 86, 563–612, 1998. Owen, C J., Fazakerley, A N., Carter, P J., Coates, A J., Krauklis, I C., Szita, S., Taylor, M. G. G T., Travnicek, P., Watson, G., Wilson, R J., Balogh, A., and Dunlop, M W.: Cluster PEACE observations of electrons during magnetospheric flux transfer events, Ann. Geophys., 19, 1509–1522, 2001. Pinnock, M., Rodger, A S., Dudeney, J R., Rich, F., and Baker, K B.: High spatial and temporal resolution observations of the ionospheric cusp, Ann. Geophys., 13, 919–925, 1995. Prikryl, P., Greenwald, R A., Sofko, G J., Villain, J P., Ziesolleck, C. W S., and Friis-Christensen, E.: Solar-wind-driven pulsed magnetic reconnection at the dayside magnetopause, Pc5 compressional oscillations, and field line ressonances, J. Geophys. Res., 103, 17 307–17 322, 1998. Provan, G., Yeoman, T K., and Milan, S E.: CUTLASS Finland radar observations of the ionospheric signatures of flux transfer events and the resulting plasma flows, Ann. Geophys., 16, 1411–1422, 1998. Rae, I J., Fenrich, F R., Lester, M., McWilliams, K A., and Scudder, J D.: Solar wind modulation of cusp particel signatures and their associated ionospheric flows, J. Geophys. Res., 109, A03223, https://doi.org/10.1029/2003JA010188, 2004. Rème, H., Bosqued, J.-M., Sauvaud, J.-A., Cros, A., Dandouras, J., Aoustin, C., Bouyssoua, J., Camus, T., Cuvilo, J., Martz, C., Médale, J L., Perrier, H., Romefort, D., Rouzaud, J., D'uston, C., Möbius, E., Crocker, K., Granoff, M., Kistler, L M., Popecki, M., Hovestadt, D., Klecker, B., Paschmann, G., Scholer, M., Carlson, C W., Curtis, D W., Lin, R P., Mcfadden, J P., Formisano, V., Amata, E., Bavassano-Cattaneo, M B., Baldetti, P., Belluci, G., Bruno, R., Chionchio, G., Lellis, A D., Shelley, E G., Ghielmetti, A G., Lennartsson, W., Korth, A., Rosenbauer, H., Lundin, R., Olsen, S., Parks, G K., McCarthy, M., and Balsiger, H.: The Cluster Ion Spectrometry (CIS) Experiment, Space Sci. Rev., 79, 303–350, 1997. Rème, H., Aoustin, C., Bosqued, J.-M., Dandouras, I., Lavraud, B., Sauvaud, J.-A., Barthe, A., Bouyssou, J., Camus, T., Coeur-Joly, O., Cros, A., Cuvilo, J., Ducay, F., Garbarowitz, Y., Medale, J L., Penou, E., Perrier, H., Romefort, D., Rouzaud, J., Vallat, C., Alcaydé, D., Jacquey, C., Mazelle, C., d'Uston, C., Möbius, E., Kistler, L M., Crocker, K., Granoff, M., Mouikis, C., Popecki, M., Vosbury, M., Klecker, B., Hovestadt, D., Kucharek, H., Kuenneth, E., Paschmann, G., Scholer, M., Sckopke, N., Seidenschwang, E., Carlson, C W., Curtis, D W., Ingraham, C., Lin, R P., McFadden, J P., Parks, G K., Phan, T., Formisano, V., Amata, E., Bavassano-Cattaneo, M B., Baldetti, P., Bruno, R., Chionchio, G., Lellis, A D., Marcucci, M F., Pallocchia, G., Korth, A., Daly, P W., Graeve, B., Rosenbauer, H., Vasyliunas, V., McCarthy, M., Wilber, M., Eliasson, L., Lundin, R., Olsen, S., Shelley, E G., Fuselier, S., Ghielmetti, A G., Lennartsson, W., Escoubet, C P., Balsiger, H., Friedel, R., Cao, J.-B., Kovrazhkin, R A., Papamastorakis, I., Pellat, R., Scudder, J., and Sonnerup, B.: First multispacecraft ion measurements in and near the Earth's magnetosphere with the identical Cluster ion spectrometry (CIS) experiment, Ann. Geophys., 19, 1303–1354, 2001. Rème, H., Dandouras, I., Aoustin, C., Bosqued, J M., Sauvaud, J A., Vallat, C., Escoubet, P., Cao, J B., Shi, J., Bavassano-Cattaneo, M B., Parks, G K., Carlson, C W., Pu, Z., Klecker, B., Kistler, E M., Korth, A., Lundin, R., and the HIA~team: The HIA instrument on board the Tan Ce 1 Double Star near-equatorial spacecraft and its first results, Ann. Geophys., 23, 2757–2774, 2005. Rijnbeek, R P., Cowley, S. W H., Southwood, D J., and Russell, C T.: A survey of dayside flux transfer events observed by ISEE 1 and 2 magnetometers, J. Geophys. Res., 89, 786–800, 1984. Rishbeth, H. and van Eyken, A P.: EISCAT: early history and the first ten years of operation, J. Atmos. Terr. Phys., 55, 525–542, 1993. Ruohoniemi, J M. and Baker, K B.: Large-scale imaging of high-latitude convection with Super Dual Auroral Radar Network HF radar observations, J. Geophys. Res., 103, 20 797–20 811, 1998. Ruohoniemi, J M. and Greenwald, R A.: Statistical patterns of high-latitude convection obtained from Goose Bay HF radar observations, J. Geophys. Res., 101, 21 746–21 763, 1996. Russell, C T. and Elphic, R C.: Initial ISEE magnetometer results: magnetopause observations, Space Sci. Rev., 22, 681–715, 1978. Russell, C T. and Elphic, R C.: ISEE observations of flux transfer events at the dayside magnetopause, Geophys. Res. Lett., 6, 33–36, 1979. Sandholt, P E. and Farrugia, C J.: Spatiotemporal structure of the reconnecting magnetosphere under B-y-dominated interplanetary magnetic cloud conditions, J. Geophys. Res., 111, A10 209, https://doi.org/10.1029/2005JA011514, 2006. Shue, J.-H., Chao, J K., Fu, H C., Russell, C T., Song, P., Khurana, K K., , and Singer, H J.: A new functional form to study the solar wind control of the magnetopause size and shape, J. Geophys. Res., 102, 9497–9511, 1997. Smith, C W., na, M. H A., Burlaga, L F., L'Heureux, J., Ness, N F., and Scheifele, J.: The ACE Magnetic Fields Experiment, Space Sci. Rev., 86, 613–631, 1998. Spreiter, J R., Sumers, A L., and Alksne, A Y.: Hydrodynamic flow around the magnetosphere, Planet. Space Sci., 14, 223–253, 1966. Stone, E C., Frandsen, A M., Mewaldt, R A., Christian, E R., Marglies, D., Ormes, J F., , and Snow, F.: The Advanced Composition Explorer, Space Sci. Rev., 86, 1–22, 1998. Trattner, K J., Petrinec, S M., Peterson, W K., Fuselier, S A., and Rème, H.: Tracing the location of the reconnection site from the northern and southern cusps, J. Geophys. Res., 111, A11 211, https://doi.org/10.1029/2006JA01167, 2006. Wild, J A., Cowley, S. W H., Davies, J A., Khan, H., Lester, M., Milan, S E., Provan, G., Yeoman, T K., Balogh, A., Dunlop, M W., Fornacon, K.-H., and Georgescu, E.: First simultaneous observations of flux transfer events at the high-latitude magnetopause by the Cluster spacecraft and pulsed radar signatures in the conjugate ionosphere by the CUTLASS and EISCAT radars, Ann. Geophys., 19, 1491–1508, 2001. Wild, J A., Milan, S E., Cowley, S. W H., Bosqued, J M., Rème, H., Nagai, T., Kokubun, S., Saito, Y., Mukai, T., Davies, J A., Cooling, B. M A., Balogh, A., and Daly, P W.: Simultaneous in-situ observations of the signatures of dayside reconnection at the high and low latitude magnetopause, Ann. Geophys., 23, 445–460, 2005a. Wild, J A., Milan, S E., Davies, J A., Cowley, S. W H., Carr, C M., and Balogh, A.: Double Star, Cluster, and ground-based observations of magnetic reconnection during an interval of duskward oriented IMF: preliminary results, Ann. Geophys., 23, 2903–2907, 2005b. Wing, S., Newell, P T., and Ruohoniemi: Double cusp: Model prediction and observational verification, J. Geophys. Res., 106, 25 571–25 593, 2001. Wing, S., Newell, P T., and Meng, C.-I.: Cusp modeling and observations at low altitude, Surv. Geophys., 26, 341–367, 2005. Wright, D M., Yeoman, T K., and Chapman, P J.: High-latitude HF Doppler observations of ULF waves. 1. Waves with large spatial scale sizes, Ann. Geophys., 15, 1548–1556, 1997. Yeoman, T K., Milling, D K., and Orr, D.: Pi2 pulsation polarization patterns on the U.K. sub-auroral magnetometer network (SAMNET), Planet. Space Sci., 38, 589–602, \mbox\doi10.1016/0032-0633(90)90065-X, 1990. Yeoman, T K., Wright, D M., Chapman, P J., and Stockton-Chalk, A B.: High-latitude observations of ULF waves with large azimuthal wavenumbers, J. Geophys. Res., 105, 5453–5462, \mbox\doi10.1029/1999JA005081, 2000.